Bushing assembly



K. DUENKE 3,084,305 BusHING ASSEMBLY 2 Sheets-Sheet 1 73 April 2, 1963 Filed Nov. 4, 1959 April 2, 1963 K. L. DUENKE 3,084,305

` BUSHING ASSEMBLY Filed Nov. 4. 1959 2 Sheets-Sheet 2 /NVE NTO/P.' KENNETH L. Jl/ENRE HTTORNE f5 site tate 3,684,305 Patented Apr. 2, 1963 3,084,305 RUSHING ASSEMBLY Kenneth L. Duenke, St. Louis, Mo., assignor to The Clarken Company, St. Louis, Mo., a corporation et' Missouri Filed Nov. 4, i959, Ser. No. @6,3% 1th Claims. (El. SEQ-2M) The present invention relates to an electrical connector or bushing and is particularly well adapted for use adjacent a power transformer, Where it is desired to maire an electrical connection between an external line and a lead to the transformer.

Specifically, the present invention contemplates certain improvements upon bushing arrangements heretofore invented by me, such as set forth in my prior application, Serial No. 572,471 led March 19, i956, now US. Patent No. 2,883,640 for Transformer Bushing Assembly.

In bushing assemblies of the type herein described, the principal object is the establishment of an electrical contact between two separate cables. Accordingly, it is a primary object of the present invention to establish such an electrical contact by way of a connector which is not only both positive in action and free from iamming, but is also readily adaptable to assembly and take-down with the use of only conventional toois. The bushing is o the type which may be more or less permanently attached to a transformer cable, but lwhich has a clamping section for attachment to a cable, which clamping section is adapted to be operated by a linesman. The clamping section is designed to accommodate an external line with which it is desired to make electrical contact to the transformer cable. When the external line is clamped into the clamping section, the internal structure of the bushing assembly will provide such electrical contact.

The transformer cable and the external line are in troduced into the bushing assembly at right angles to one another. lt has been found that the most positive acting clamping means in such a bushing assembly as herein described is that clamping means which engages a maximum portion of the external line. Accordingly, it is another object of the invention to provide in a bushing connector, a clamping means which engages the external line over a maximum surface area of that line.

With the clamping means engaging the external line over a maximum external area, being along its length, the movable shoe which comprises one jaw of the clamping means is elongated at right angles to its direction of movement as it is forced against and drawn away from the external line which it clamps. It is a special obiect of this invention to provide means for attaching such a shoe to a rotatable shaft, which shaft causes the aforesaid movement of the shoe, wherein the means of attachment are readily accessible to a linesman so that assembly and take-down may be accomplished by ordinary tools.

Further objects and advantages of the invention will become apparent from the more detailed description.

In the drawings:

FIGURE l is a view taken along the length of the bushing assembly with parts shown in section to illustrate certain details of the assembly.

FIGURE 2 is a view similar to FlGUlE l but taken at right angles thereto;

FlGURE 3 is a view in section taken along the lines 3--3 of FlGURE 2;

FIGURE 4 is a view in 4 4 of FIGURE l;

FIGURE 5 is a partial View similar to that of FlGURE 4 but showing the shoe in an elevated position;

FIGURE 6 is a view in section taken along the lines 6 6 of FlGURE 4;

FIGURE 7 is a detailed plan embodying this invention;

section taken along the lines view of the shoe and stud FGURES 8 through l5 illustrate an embodiment of a modification wherein,

FIGURE 8 is a View in section of the modification similar to the corresponding portion illustrated in Eli@ URE l;

FIGURE 9 is a view similar to FGURE S but taken from the left side of FGURE 8;

ElGURE l0 is a view in section taken along the lines itl-lib of FIGURE 9;

FIGURE l1 is a view in section taken along the lines lll-ll of FIGURE 8;

FIGURE 12 is a -View in section taken along the lines lZ--lZ of FlGURE ll;

FiGURE 13 is a plan View of the connecting clip er--- ployed in the modi'iication of FEGURE 8;

FIGURE 14 is a view in section of the connecting clip taken along the lines it- 142' of FIGURE 13; and

FlGURE l5 is a plan view of the modication of FlG- URE 8 but with the cap and clamp members removed.

In FIGURE l, numeral Ztl designates generally a portion of the bushing assembly which incorporates the improvements of this invention. inasmuch as the connecting means is vfully shown in elevation in FGURES l and 2 and, inasmuch as the surrounding insulation represents only an illustrative housing for the connectingj means, that surrounding insulation is shown only partially and diagrammatically in section.

rihe insulator housing 2li may be conventionally constructed of porcelain. lt should have a recess 22, which is circular, extending through one end of it to a position whereat the recess 22 enlarges to form a shoulder 23 and a larger cylindrical shaped passage 24. A porcelain ring 25' has an exterior diameter approximately equal to the diameter of the enlarged passage 2li so that the ring 25 is seated within the enlarged passage 24 upon the shoulder 23. Preferably, the ring Z5 is presstted within the passage Z4 by a conventional heat-treatment process. The ring 25 has a hole 26 through it, which affords a channel for an electrical contact to be described. ln such configuration, the ring Z5 acts as a bearing surface for the elements which are to contribute to the electrical contact.

One of these elements is a cable 29, such as the one which connects to a transformer. Such cable 29 has its end trimmed of insulation, as at Sii, so that it makes an electrical contact with a plug 3l, the cable Z9 is held to the plug 3l by insertion of the bare end 3@ into a recess 32 extending into the plug 3l at one end 33 thereof. The plug 3i is constructed of copper or bronze or other electrical conducting material and has its end 35 opposite the recess 32 shaped to form a threaded stud. An enlarged portion 36 between the recess 32 and the stud 3-5 provides a shoulder 37 upon which a washer or ring 38 may be seated. The washer or ring 38 has an external diameter which is larger than the diameter of the lhole 26 through the ring Thus, with the plug 3l placed upon the bared end 3@ of a transformer cable 29, and a washer 3d placed upon the shoulder 37 of the plug 3l, the porcelain housing El. of the bushing connector 2li is placed with the recess 22 over the plug 3l so that the ring Z5 carried. by the porcelain housing 2l will engage and rest upon the washer 38. ln this position, the stud por-tion of the plug 3l projects through the hole 2.6 ready for threaded engagement with the clamping assembly dil.

The improvements contemplated by this invention are centered about the clamping assembly now to be described. That assembly includes a hous'mg 4l cast of bronze or other electrically conducting substance. in the embodiment illustrated by ElGURES l through 7, the casting 4l includes a relatively narrow section 42 which has a hole 43 through it. rPhe hole 43 has `a top surface 4d, a pair of parallel side surfaces and d6, and a lower surface a7 parallel to the top surface d4 but having a ll-groove Llil along the length of its center. A threaded hole communicates the cutout 43 with the top d@ of the casting.

A tapped hole ft extends through the portion 42, of the casting fil in horizontal communication with the opening 43 immediately above the lower surface i7 thereof. The tapped hole 54 provides a means of threaded engagement of the casting 41 with a sparkgap member 55 of which the grounding functions are well known in the art.

Below the cutout 43, the casting fill includes a flared skirt section 58 which has an annular indentation 59 in it. The indentation 59 terminates centrally at the exterior wall @il of a circular projection el from the casting di. The projection el includes a tapped hole 62 adapted for threaded engagement with the stud section 35 of the plug Bil. A gasket ed. is of proper external and internal diameters to be seatable within the indentation 59 of the casting It will be apparent that the casting 41 is placed within a chamber 65 in the housing 2li, which chamber communicates with the hole 26 through the ring 25. Within the chamber 65, the casting 4l is threaded onto the stud portion 35 of the plug Si, a distance determined partially by the bearing of the washers 3d and 6ft against the ring member as the plug 33t and the casting dit are threaded together. The nal determinant of the rotative position of the casting lill, however, is the coincidence of the spark gap member 55 with a hole 68 in the porcelain housing 21, through which the spark gap member 55 may pass. It may lbe noted that when the casting il is so aligned relative to the hole 68, the opening 43 will be aligned with a pair of holes 69 through the housing 2i through which the external line to be clamped passes.

A threaded -shaft 72, which is presst and preferably glued or otherwise xedly secured to a cap 73, is turned into the @threaded hole 4l@ of the casting 4l. For instance, the cap 73 may be of any suitable shape so long as it is freely rotatable, with the shaft 72, relative to Ithe porcelain housing 21. The cap 73 may be formed of phenolic resin or other insulating material .so that it may be grasped and rotated by a linesman, thereby r0- tating the threaded shaft 72 for further projection of that shaft within the threaded hole 49 of the casting 41.

An end 74 of the shaft 72 is tapped at 75 to receive the stud end 76 of a short shaft 77. The shaft 77 has a head 78 at its opposite end, which has a conventional screw driver groove 79 in it.

A clamping shoe Sli is adapted to be lit over the shaft '77 and to be retained by the head 78 upon the shaft 77. For this purpose, the shoe 3@ (which is of horizontally elongated shape), is bored at 3l through part of its height, as illustrated in FlGURE 4. The bore 31 is of slightly larger diameter than the `diameter of the shaft head 78 so that the shaft head 73 can pass through 4the bore dil. Gffset from and in communication with the bore 831 is a second bo-re 82 which is of the same diameter as the bore 811. and which, at its place of communication with the bore 8l extends above the lower sur* face of that bore @l by a distance at least slightly greater than the vertical thickness of the shaft head '78. A slot 33 immediately above the 4bore 82 is vco-axial with the bore 82 (but of smaller diameter), and, at the same time, has one of its ends S3 in open communication with the bore 3l. As can `be seen from FIGURES 6 and 7, the communication of the slot 83 with Ithe bore ll resembles a keyway in shape. It should be appreciated that, as the shoe 80 is placed beneath the shaft 77, the head 7S of the shaft 77 may pass within the bore 8l. When the head 78 bottoms upon the bottom of the bore 3l, the shoe Sil may be slid horizontally with the bore 32 approaching the head 78. As the shoe Sil is slid toward the left, as viewed in FlGURE 4, the slot :'33 in the shoe accommodates the shaft 77 so that the head 7b of the shaft may be positioned below the slot 83. Since the head 7S of the shaft 77 is of larger diameter than the slot 83, the shoe itil is held against downward vertical movement `by the head 73 when the shaft is positioned within the slot 83.

The end of the shoe il@ which is nearest the bore 8l is threaded at h5 to accommodate a locking screw 3d `which is threaded into the tap ed hole 8S. The locking screw 5 is of such a length that it may abut against the head 7S of the shaft 77 when that shaft is positioned within the slot lr. (See FGURE 4.) Thus, when the Vlocking screw 86 is threaded completely Within the tapped hole d5, the shaft 77 is locked into co-axis with the bore $2 so that the shoe may not move vertically downward.

A compression spring i525 is placed upon the shaft 77 so as to bear between the stud 72 and the shoe di) and thereby continuously urge the shoe downwardly against the head 7S of the shaft 77.

As can be seen from FGURES 3 and 4, the shoe Sil has a groove 9@ at its center which is il-shaped along the length of the shoe E@ and which is opposite the groove 8 in the casting di. lt will be apparent that when a cable projects through an opening 69 in the body 2l through the area between the lower surface 47 of the casting l1 and the shoe dit, it may he clamped between the V-grooves 43 and @il of the casting' and shoe, .respeetively, ywhen the shoe is forced against such cable by rotation of the cap 73. Such clamping action is positive because the shoe Sil is guided by the vertical walls #to of the casting fil, and the shaft 77 is freely rotatable relative to the shoe 8i?.

lt can be seen that the release of the shoe titl from the bushing assembly entails only the removal of the stud Se by means of an ordinary screwdriver. When the stud Se is either removed or extracted so as to be free of the bore Si, the shaft 77 may be slid relative to the shoe di? so that the head 7h of the shaft 77 lies within the bore Si. ln this position, the head 78 will freely pass by way of the bore Sil from within the shoe titl and the shoe dit will be freed from the shaft 77 for complete removal from the bushing assembly 2i). lt may be noted that the bore 82 by extending through the lower side of the shoe 8l) provides a means of removal of the shaft 77 through the use of a right-angle screw-driver if such removal is desired To employ the bushing assembly 2i? for the purpose of connecting an external wire to a transformer cable 29, it should be readily apparent that the transformer cable 29 is secured to a plug 31 by stripping an end 3@ of the cable 29 and establishing an electrical contact of the cable 29 with the plug 3l (which is electrically conductive). The plug 31 carrying the transformer cable 29 is inserted into the recess 22 of a housing 2l until the washer 38 carried by the plug 3i abuts the ring 25 which has been force-'ittingly secured into the recess 2d of the housing 2l. Next the housing il of the clamping assembly lll is turned onto the stud 35 of :the plug 3l. until the washer ed carried by the casting di. is drawn tight against the ring The casting il is electrically conductive so that electrical impulses received by itcare transmitted by way of the stud 35 to the transformer cable 29.

The external wire has its bared end inserted through Vthe opening 69 of the housing into the area between the V-groove 48 and the V-groove @il of the shoe 3d. The cap 73 is then rotated so that the shaft 77 carried thereby urges the shoe dll downwardly toward the external cable clamping the same between the shoe and the V-groove 4,8. An electrical connection is accordingly established between the external cable, the casting il and the transformer lead 29.

The shoe il@ may be removed from the bushing assembly Zt by the simple removal of the stud 86 or the turntoscana ing of 4the stud 85 outwardly vfrom the shoe 80 so that it .does not interfere with the bore l31. After the Stud 86 has been so extracted, the head 7S of the shaft 77 is slid longitudinally from the lbore 82 to the bore 81, and thereafter the shaft 77 may pass from the shoe `80 so that the shoe S `can be extracted from the housing 21 through the opening 69 thereof.

In the modification illustrated in FGURES 8 through l5, the housing configuration remains the same. Likewise the connection of `the transformer cable 29 to the plug 31 and the establishment of Van electrical connection with the plug 31 and Ithe bushing 41 are unchanged.

The housing 110 for the embodiment presently being described is also threaded at a bore 111 to receive the stud 72 of the operating handle. However, this housing 110 is illustrated as having a pair of opposed tapped holes 112 and 113, either one of which may receive the spark gap member 55. Thus, as the housing 11? is rotated onto the stud 35, veither the tapped hole 112 or 113 may be aligned with the ,opening 6d depending upon which one is closer to it after the housing 110 has been completely tightened Onto `the stud A35.

The` casting 110 has an opening 115 through it whose axisis normal to the axis of the holes 112 and 113. The hole 115 has a top surface 11,6, side surfaces 117 and 113 `and a lower V-shaped surface 11%. The surface 119 is illustrated as being of more gradual V-shape than the surface 47 of the previously described embodiment.

As illustrated in FIGURE l2, the surfaces 117 and 118 of the casting 11i) have vertically extended cut-out sections 120 and 121 at approximately the center of each surface 117 and 118. These cut-out sections are intended to accommodate a uniquely formed shoe 125. Again, as illustrated in FIGURE 12, the plan view of the shoe 125 shows that it includes wings 126 and 127 at its ends. Separating the wings 126 and 127 is a generally circular center 12S. The center of the shoe 125 has a vertical bore 131i which will be larger' than the head of the shaft 77 so that the head of the shaft 77 may `freely pass through the bore 130. In addition, there is a horizontal tapped hole 131 through the shoe 125 communicating the bore 130 with the right end of the shoe, as viewed at FIG- URE ll.

A locking clip 135 is illustrated in FIGURES 13 and 14 as having two legs 136 and 137 at right angles to one another. The leg 136 has a slot 13S in its end and the leg 137 has a hole 139 through it. The hole 139 is spaced from 4the leg 136 a distance corresponding to the spacing of the tapped hole 131 from the upper surface of the shoe 125. Thus, in the assembly iwhich is illustrated particularly in FIGURE 1l, the locking clip 135 is attached to the shoe 125 by a screw 1d@ which passes through the hole 139 and is threaded into the tapped hole 131. The attachment of the clip 1.35 to the shoe 125 is performed after the shoe 125 has been placed into the bushing assembly so that the sha-ft '77 has its head inserted into the bore 130. Therefore, the slot 138 of the leg 136 permits the forks adjacent the slot 133 to extend on either side of the shaft '77.

With the shoe 125 thus installed upon the shaft 77, the bushing assembly modification of FIGURES 8 through operates in imuch the same manner as the modification first described. That is to say, fthe shoe 125 is made to clamp an external wire between it and the surface 119, as fthe handle which rotates the shaft 72 is turned by a linesman.

To remove the shoe 125, it is -only necessary that the stud 140, which is accessible from the exterior of the assembly, be removed by means of a conventional screwdriver. When the stud 140 has been removed, the locking clip 135 can be slid 'away from its position straddling the shaft 77 so as to release the head of that shaft.

Many bushing connectors of fthe type herein described are used to connect cables which comprise multiple strands of wire. In many such connectors, it :as been found. that one of the strands of wire .from ther cable will become wedged between the shoe and the shoe casting. Ilt will Ibe appreciated that, from the unique shape of the shoe in cooperation with the casting 110, there is no straight line space between those members, so that a straight strand of wire in a cable `may not drop between fthe shoe 125 land the casting 110.

What is claimed is:

l. In a bushing connector having electrically conductive receiving means for an electrical cable yand having clamping means for an external cable, which clamping means is in electrical contact with the receiving means with a rotatable shaft including an enlarged shaft head being provided to control the clamping means, la connector shoe movable against an external wire to clamp the same; the shoe being elongated and having means for rotatable securernent to the headed shaft, the securement means being releasable upon `sliding the shoe transversely to the axis of the shaft, movable means positionra-ble adjacent the securement means land movable away from the securement means for releasing the headed shaft upon sliding at least part lof said shoe transversely to the axis of said shaft, comprising a stud extendable within the shoe from one end thereof for abutting 'the shaft head to prevent sliding any part of the shoe transversely Ito the axis of the shaft.

2,. A bushing connector ycomprising `an electrically conductive housing having `an opening through it, means for connecting an electrical cable to the housing, the opening having la bottom wall, block `means slidable within the opening toward and away from the bottom wall, a .tapped hole through the housing and communicating with the opening opposite the bottom wall, a shaft threaded through the tapped hole, with an end extending into the opening, an enlarged head on the end of the shaft within the opening, Ithe block means having la recess in it large enough to receive fthe shaft head, a slot in the block means communicating with the recess, lthe slot being large enough to receive the shaft but too small to receive |the shaft head, at least that portion of the block means containing the slot being slidable relative to the shaft to free the shaft head from the slot, land screw means accessible externally of the housing for locking the block means Iagainst releasing the screw head from the slot.

3. The connector of claim 2 wherein the opening in the housing has side walls defined by the movement of .a vertical line along la crooked path and wherein the block means has -sides of the same general shape as the side walls so that fthe distance between opposite points on the hou-sing side walls is less than that between opposite points on the sides of the block means measured at planes of minimum 'and maximum width, respectively.

4. A bushing assembly lfor clamping two separate electrical cables while providing an electrical connection between the cables comp-rising la housing formed of an iusul-ator material, `a housing formed of an electrically conductive material contained Wirth-in the insulator housing, a first recess through the insulator housing, means on the conductive housing rand adjacent the recess for fastening an end of an electrical cable to the conductive housing, la passage through the conductive housing, one side of the passage providing a jaw of a clamp, an elongated shoe slidable within the passage toward rand away from the jaw side of the passage, the passage having sides for preventing rotation of the shoe, a recess within the shoe, a shaft threaded through the conductive housing so that one end extends within the passage, a pin `on the one end of the shaft, an enlarged head on the end of the pin extendable within the shoe recess, means for releasiably blocking the removal of the pin head from fthe shoe recess, ,a pair of openings through opposite sides of the insulator housing, each adjacent to an opposite end of the passage for permitting la cable to extend through the insulator housing and between .the jaw ,and the shoe, the shoe being small enough to pass through one of the pair of openings, the shoe being movable into a position for clamping the `cable against the jaw, :a stud alternately `movable toward and away from a position for blocking release of the pin head from the blocking means, the axis of the stud being substantially parallel t-o the axis of the passage `and the head of the stud lbeing accessible from one lof the openings.

5. The bushing assembly of `claim 4 wherein the shoe recess comprises lan opening within fthe shoe larger than the head of the pin and a slot through at least part of the side of the shoe nearest the shaft, the slot being positioned alongside and communicating with the shoe opening and having one dimension that is greater than the diameter of the pin and less `than the `diameter of Ithe pin head so that the shoe is held to the pin when the pin is positioned within the slot, the stud being extendable through the shoe opening and into the slot for blocking the removal `of the pin from the slot.

6. The bushing assembly of claim 5 with resilient means for pressing the shoe against the pin head when the pin is within the slot.

7. rPhe bushing :assembly `of claim 5 wherein the height of the slot measured from the side of the shoe nearest Ithe shaft is less than the height of the shoe by at least the height of the pin head.

8. The bushing assembly of claim 7 wherein the shoe opening extends through the shoe a distance at least equal to the sum of the heights of the slot `and the pin head.

9. The bushing assembly of claim 4 wherein lthe block ing means comprises a clip, the clip being formed as two legs :at Ian .angle to one another, one leg of the clip having a bifurcated end for positioning about the pin above the pin head when in blocking position, the other by being attachable tto an end of the shoe by the stud.

l0. The .bushing assembly of claim 9 wherein the passage through the conductive housing has irregularly shaped side walls and the shoe has corresponding irregularly shaped sides, part :of each side wall of the passage extending inward of the outer extreme of Kthe -adjacent shoe side.

References Cited in the le of this patent UNITED STATES PATENTS 1,768,364 Lawton June 24, 1930 1,916,488 Parrish July 4, 1933 1,968,736 Bodendieck July 31, 1934 2,161,249 Dibner June 6, 1939 2,353,114 Novak July 4, 1944 2,506,010 B-irkenmaier May 2, 1950 2,508,778 Spears May 23, 1950 2,597,070 Cook et al. May 20, 1952 2,740,100 Broverman Mar. 27, 1956 2,883,640 Duenke Apr. 21, 1959 FOREIGN PATENTS 394,042 Germany Apr. 12, 1924 

1. IN A BUSHING CONNECTOR HAVING ELECTRICALLY CONDUCTIVE RECEIVING MEANS FOR AN ELECTRICAL CABLE AND HAVING CLAMPING MEANS FOR AN EXTERNAL CABLE, WHICH CLAMPING MEANS IS IN ELECTRICAL CONTACT WITH THE RECEIVING MEANS WITH A ROTATABLE SHAFT INCLUDING AN ENLARGED SHAFT HEAD BEING PROVIDED TO CONTROL THE CLAMPING MEANS, A CONNECTOR SHOE MOVABLE AGAINST AN EXTERNAL WIRE TO CLAMP THE SAME; THE SHOE BEING ELONGATED AND HAVING MEANS FOR ROTATABLE SECUREMENT TO THE HEADED SHAFT, THE SECUREMENT MEANS BEING RELEASABLE UPON SLIDING THE SHOE TRANSVERSELY TO THE AXIS OF THE SHAFT, MOVABLE MEANS POSITIONABLE ADJACENT THE SECUREMENT MEANS AND MOVABLE AWAY FROM THE SECUREMENT MEANS FOR RELEASING THE HEADED SHAFT UPON SLIDING AT LEAST PART OF SAID SHOE TRANSVERSELY TO THE AXIS OF SAID SHAFT, COMPRISING A STUD EXTENDABLE WITHIN THE SHOE FROM ONE END THEREOF FOR ABUTTING THE SHAFT HEAD TO PREVENT SLIDING ANY PART OF THE SHOE TRANSVERSELY TO THE AXIS OF THE SHAFT. 